import 'package:flutter/material.dart';
import 'conversation_page.dart';
import 'contacts_page.dart';
import 'discover_page.dart';
import '../constants.dart' show Constants, AppColors;

enum ActionItems {
  GROUP_CHAT, ADD_FRIEND, QR_SCAN, PAYMENT, HELP
}

class NavigationIconView {

  final BottomNavigationBarItem item;

  NavigationIconView({Key key, String title, IconData icon, IconData activeIcon}):
      item = new BottomNavigationBarItem(
          icon: Icon(icon),
          activeIcon: Icon(activeIcon),
          title: new Text(title),
          backgroundColor: Colors.white
      );
}

class HomeScreen extends StatefulWidget {

  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {

  PageController _pageController;
  List<Widget> _pages;

  int _currentIndex = 0;
  List<NavigationIconView> _navigationViews;

  @override
  void initState() {
    super.initState();
    _navigationViews = [
      NavigationIconView(
        title: "微信", 
        icon: IconData(
          0xe608,
          fontFamily: Constants.IconFontFamily,
        ),
        activeIcon: IconData(
          0xe603,
          fontFamily: Constants.IconFontFamily,
        ),
      ),
      NavigationIconView(
          title: "通讯录",
          icon: IconData(
            0xe601,
            fontFamily: Constants.IconFontFamily,
          ),
          activeIcon: IconData(
            0xe656,
            fontFamily: Constants.IconFontFamily,
          )
      ),
      NavigationIconView(
          title: "发现",
          icon: IconData(
            0xe600,
            fontFamily: Constants.IconFontFamily,
          ),
          activeIcon: IconData(
            0xe671,
            fontFamily: Constants.IconFontFamily,
          )
      ),
      NavigationIconView(
          title: "我",
          icon: IconData(
            0xe6c0,
            fontFamily: Constants.IconFontFamily,
          ),
          activeIcon: IconData(
            0xe626,
            fontFamily: Constants.IconFontFamily,
          )
      ),
    ];
    _pageController = PageController(initialPage: _currentIndex);
    _pages = [
      ConversationPage(),
      ContactsPage(),
      DiscoverPage(),
      ConversationPage()
    ];
  }

  _buildPopupMenuItem(int iconName, String title) {
    return Row(
      children: <Widget>[
        Icon(IconData(
            iconName,
            fontFamily: Constants.IconFontFamily
        ), size: 22.0, color: const Color(AppColors.AppBarPopupMenuTextColor)),
        Container(width: 12.0,),
        Text(title, style: TextStyle(color: const Color(AppColors.AppBarPopupMenuTextColor)),)
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    
    final BottomNavigationBar botNavBar = new BottomNavigationBar (
      fixedColor: const Color(AppColors.TabIconActive),
      items: _navigationViews
          .map<BottomNavigationBarItem>((NavigationIconView navigationView) => navigationView.item)
          .toList(),
      currentIndex: _currentIndex,
      type: BottomNavigationBarType.fixed,
      onTap: (int index){
        setState(() {
          _currentIndex = index;
          _pageController.animateToPage(_currentIndex,
              duration: Duration(milliseconds: 200), curve: Curves.easeInOut);
        });
      },
    );
    
    return Scaffold(
      appBar: AppBar(
        title: Text('微信'),
        // 去除阴影
        elevation: 0.0,
        actions: <Widget>[
          IconButton(
            icon: Icon(IconData(
              0xe65e,
              fontFamily: Constants.IconFontFamily
            ), size: 22.0,),
            onPressed: () {
              print('点击了搜索');
            },
          ),
          Container(width: 16.0),
          PopupMenuButton(
            itemBuilder: (BuildContext context){
              return <PopupMenuItem<ActionItems>> [
                PopupMenuItem(
                  child: _buildPopupMenuItem(0xe69e, '发起群聊'),
                  value: ActionItems.GROUP_CHAT,
                ),
                PopupMenuItem(
                  child: _buildPopupMenuItem(0xe638, '添加朋友'),
                  value: ActionItems.ADD_FRIEND,
                ),
                PopupMenuItem(
                  child: _buildPopupMenuItem(0xe61b, '扫一扫'),
                  value: ActionItems.QR_SCAN,
                ),
                PopupMenuItem(
                  child: _buildPopupMenuItem(0xe62a, '收付款'),
                  value: ActionItems.PAYMENT,
                ),
                PopupMenuItem(
                  child: _buildPopupMenuItem(0xe63d, '帮助与反馈'),
                  value: ActionItems.HELP,
                ),
              ];
            },
            icon: Icon(IconData(
                0xe658,
                fontFamily: Constants.IconFontFamily
            ), size: 22.0,),
            onSelected: (ActionItems selected) {
              print('点击的是$selected');
            },
          ),
          Container(width: 16.0),
        ],
      ),
      body: PageView.builder (
        itemBuilder: (BuildContext context, int pageIndex){
          return _pages[pageIndex];
        },
        controller: _pageController,
        itemCount: _pages.length,
        onPageChanged: (int index) {
          setState(() {
            _currentIndex = index;
          });
        },
      ),
      bottomNavigationBar: botNavBar,
    );
  }

}

